1. Field of the Invention
The present invention relates generally to a planar light beam orientation device and more particularly to a planar light beam orientation device capable of projecting a 360.degree. planar beam.
2. Description of the Related Art
In the practice of dentistry, the making of removable partial dentures is a very exacting process. Careful planning on the part of the dentist is required prior to making the partial denture so that optimum fit and comfort are achieved for the patient.
This planning process requires a careful analysis of models of the patient's teeth, also known as dental casts. This analysis is performed on a device known as a dental surveyor. A dental surveyor is comprised of a horizontal platform to which a vertical arm is affixed. At the top of the vertical arm is an arm projecting horizontally over the surveying platform. This horizontal arm extends to the midpoint of the surveying platform. At the free end of the horizontal arm is a receptacle adapted for receiving a movable downward extending arm. The movable downward extending arm extends vertically towards the surface of the surveying platform and is adapted at its inferior end, i.e., the end projecting towards the surveying platform, to receive various attachments, including a marking stylus. A dental surveyor is also comprised of a surveying table on which a dental cast may be mounted.
The surveying table is adapted so that the surface to which the dental cast is mounted can be reversibly positioned in a given orientation. The surveying table allows for the surface to which the cast is mounted to be tilted in three planes until the optimal orientation is achieved. The cast is then immobilized in that chosen position.
The downward extending arm of the surveyor is positioned so that the marking end of the stylus is in an appropriate horizontal plane with the mounted cast. The stylus is then used to mark the mounted cast in at least three positions. This procedure of marking of the cast is known as tripodization of the cast. The marks on the dental cast all lie in the same horizontal plane which is likewise parallel to the surveying platform. These marks are unique to the marked cast and will be used for subsequent reorientation of the cast and the surveying table in relation to the surveying platform.
A dentist may have dental casts for a number of patients that he may wish to survey for removable partial dentures or for other procedures. Moreover, he may need to remount and reorient a dental cast to re-evaluate a design or for other reasons. Accordingly, the ability to accurately reorient previously evaluated casts is imperative.
Presently, reorienting a previously evaluated dental cast is very much a trial and error process. That is, the dentist or technician must, through continual tilting adjustments of the surveying table, attempt to orient the surface of the surveying table holding the cast so that the horizontal plane created by the stylus marks on the cast is again parallel to the surveying platform. Accordingly, the stylus is moved vertically until the stylus contacts a single mark on the dental cast and then the surveying table holding the dental cast is tilted or adjusted until the other two markings are brought into the same plane. This is a frustrating and time consuming procedure.
Accordingly, a need exists for an apparatus and method making orienting and reorienting dental casts in relation to a dental surveyor easier and more efficient. The present invention meets that need.